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an it Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE CLEO H. KIDWELL, OF WEST NEW BRIGHTON, NEW YORK, ASSIGNOR TO KIDWELL &; COMPANY, INC., A CORPORATION OF NEW YORK METHOD OF REMOVING INK SPOTS AND THE LIKE No Drawing.

The present invention relates to a method Application filed January 4, 1924. Serial No. 684,301.

The strength of solutions used and the of removing spots or stains from clotg p ap er length of time of the treatments may Vary and like nat eria l, ljl e nventfin is particu'la1ly adapted to remove spots containing iron compounds, such for example as commercial blue-black writing fluids, rust spots, etc., although many ink spots containing merely .a dye can be removed by my treatment.

So far as I am aware, eradicators heretofore used have been unsatisfactory in that they do not completely remove the spot or, if the spot is removed, the color has been taken out of the material leaving a mark almost as noticeable as the original spot. Also, many of the eradicators now used injure the cloth itself. In general the commercial ink eradicators heretofore used contain bleaching or oxidizing agents which bleach the material to a greater or less extent. Delicate dyes in particular are invariably attacked and faded by eradicators which are based on an oxidizing or bleaching action.

The present invention contemplates the removal of ink spots and the like by a simple treatment which will completely remove the spot without attacking the original coloring or the dye in the material, and without injuring or tendering the material in any respect. My improved method does not inypl e a bleachin treat m ent as V1 e at once 5 ar'fifiiinae skilled in the art when the treatment is hereinafter described in detail. My method may be used on any material Without fear of deleterious effect. For example, silk and silk dyes which are attacked and injured by other eradicators, are not affected by my treatment.

Broadly stated, my improved method of removing spots consists in the treatment of the spotted material with a solution containing a sulphide or polysulphide (for example,

sodium sulphide or .amm gn i um sulphidg),

45 dilute solution of an acid, for example, oxalic with the particular material to be treated and the character of the spot. So also the particular method of subjecting the spotted material to the solutions may vary widely. Accordingly I shall not endeavor herein to describe all the ways in which my invention may be practiced, but in order that those skilled in the art may understand the invention fully (30 I shall, for purposes of illustration merely and not with the intention of limiting the scope of the invention in any respect, describe one way in which I have applied the invention With excellent results. 05

The fabric whose treatment I am about to describe is a cotton fabric, of the type commonly used in handkerchiefs, and having therein a large ink spot. I first dip this fabric in water and moisten it thoroughly.

mersed for ten or fifteen seconds in a five so (5%) percent solution, by weight, of oxalic acid. I then remove the fabric and wash it thoroughly in water before drying. In most cases the spot is completely removed by this treatment, but if any trace of the spot should remain, it will be necessary only to go through this treatment a second time in order to eradicate the spot entirely.

The terms and expressions which I have employed are used as terms of description and so not of limitation, and I have no intention, in the use of such terms and expressions of excluding any equivalents of the features shown and described, or portions thereof, but

recognize that various modifications are possible within the scope of the invention claimed.

What I claim is:

1. The method of removing spots contain- Ten or fifteen 75 ing an iron compound which consists in treat- -1 ing the spot with a solgble sulphide, substantially removing tfie excess sulphide, if any, and then treating aislspnt..iszlruhaiilutss9:

without siilostantial oxidation or reduction to form a water soluble iron salt.

2. The method of removing spots containing an iron compound Which consists in treating the spot with the sulphide of an alkali metal, substantially removing the excess sulphide, if any, and then treating the spot with a dilute solution of an acid that reacts on iron sulphide without substantial oxidation or reduction to form a water soluble iron salt.

3. The method of removing spots containing an iron compound which consists in reducing the iron compound to iron sulphide by treatment with sodium sulphide, substantially removing the excess sulphide, if any, and then dissolving the iron sulphide in a dilute solution of oxalic acid.

4. The method of removing spots containing an iron compound which consists in treating the spot with a 5% solution, by weight, of sodium sulphide, substantially removing the excess sulphide, if any, and then acidulating 'said spot with a 5% solution, by weight, of

oxalic acid.

5. The method of removgn spots contain- I Wm ay *fiW-av'iwmswe ing an 1I0I1 comnoundffrom cloth, paper or the like which conslst inmoistenlng the spotted portion with water, wetting it thoroughly with a 5% solution, by weight, 0 p V phide, gvashipg ogt the excess sodium sulphide with water, then acidulating the said spotted portion with a 5% solution, by

Weights f acid an i thorough y.

6. The method of removing spots containing an iron compound which consists in precipitating the iron by treatment with a soluble sulphide, substantially removing the excess sulphide, if any, and then removing the precipitate by treatment with a dilute solution of an acid that reacts on iron sulphide without substantial oxidation or reduction to form a water soluble iron salt.

7 The method of removing spots contain- -ing iron compound which consists in precipitating the iron by treatment with the sulphide of an alkali metal, substantially removing the-excess sulphide, if any, and then removing the precipitate by treatment with a dilute solution of an acid that reacts on iron sulphide without substantial oxidation or reduction to form a Water soluble iron salt. CLEO H. KIDWELL. 

